The invention relates to a substrate treatment system having a transportation device for transporting substrates.
Typical substrate treatment systems for carrying out substrate treatment operations in a continuous process comprise an elongate system chamber having an entry lock at one end and an exit lock at the other end and also functional regions which are arranged between the said locks, for example one or more treatment regions with in each case at least one substrate treatment device, for example a coating device, an etching device, a heating device or the like, one or more pump regions with in each case at least one pump for evacuation or/and for atmospheric separation between functional regions situated upstream and downstream of the said pump, transfer regions for transferring the substrates from one functional region to the next functional region etc.
In this case, the functional regions which are defined by their function can form physically independent containers, which are connected to one another to form a system chamber, or can be arranged inside a common container which forms the system chamber. In the latter case, the functional regions can be physically bounded from one another by separating walls which typically have a substrate passage which can be designed as a flow resistor, that is to say as an opening of a size which still just permits the passage of the substrates, or as a valve, for example a check valve, roll valve or slider valve.
In substrate treatment systems of this kind, for example systems for coating or/and for dry-etching plate-like substrates, transportation devices are known, these transportation devices having an arrangement of transportation wheels or transportation rolls on which the substrates are transported in the transportation direction, in a vertical or horizontal position, from the entry lock to the exit lock through the substrate treatment system and, in the process, through the functional regions arranged between the said locks. In this case, the substrates can be supported by a substrate holder which is moved by the transportation device or can be moved through the substrate treatment system without a substrate holder, that is to say directly on the transportation device in a horizontal or vertical position.
In this case, a transportation roll is to be understood to mean an elongate, substantially cylindrical body which is rotatably mounted, for example in a typical transportation device for the horizontal (recumbent) transportation of plate-like substrates, at each of the two ends of the said transportation device, it being possible for a plurality of transportation rolls to be mounted, for example by way of each end, in a respective bearing support, the bearing supports in each case having the bearings for a plurality of transportation rolls which are arranged one behind the other in the transportation direction of the substrates. A transportation device of this kind is described, for example, in DE 10 2005 016 406 A1.
In contrast, for the purposes of this description, a transportation wheel is intended to be understood to mean a relatively short, substantially cylindrical body (with or without circumferential guide channels) which is rotatably mounted, for example in a typical transportation device for the vertical (upright or slightly inclined from the vertical) transportation of plate-like substrates, at only one of the two ends of the said transportation device. A plurality of transportation wheels can also be mounted, for example by way of one end, in a bearing support, the bearing supports in each case having the bearings for a plurality of transportation wheels which are arranged one behind the other in the transportation direction of the substrates. As an alternative, the bearings can also be arranged in a chamber wall of the substrate treatment system. A transportation device of this kind is described, for example, in DE 10 2007 052 524 A1.
For reasons of linguistic simplicity, transportation rolls and transportation wheels of the above-described type will both be referred to as transportation rollers in the text which follows.
In known transportation devices, the transportation rollers are actively driven, that is to say a drive device, for example an electric motor, is provided, this drive device driving a plurality of transportation rollers which are coupled by mechanical transmission means, for example chains, toothed belts, vertical shafts or the like. The transportation rollers can be coupled to one another inside or outside the system chamber.
If the transmission means is located, and therefore the transportation rollers are coupled, outside the system chamber, the drive device can be arranged outside the system chamber, this being advantageous for substrate treatment operations under vacuum or at high temperatures. However, the drive torque for generating rotation of the transportation rollers has to be transmitted by rotary leadthroughs from outside to inside the system chamber in this case. Coupling of the transportation rollers outside the system chamber requires a respective rotary leadthrough for each individual transportation roller, this being reflected in the price of the substrate treatment system. At the same time, a large number of potential leakage points are produced, these having to be carefully sealed off.
If the transmission means is located, and therefore the transportation rollers are coupled, inside the system chamber, problems arise in respect of component and material selection and the installation site, especially in the case of hot processes or critical necessary gas separation. The known transmission means are subject to mechanical wear. Furthermore, the length of the transmission means changes as temperatures change and there is a risk of the process atmosphere being contaminated by the transmission means.
Proceeding from this prior art, an aspect of the present invention is to improve known continuous substrate treatment systems.
This aspect is achieved by a substrate treatment system having the features of the present invention. Refinements and developments are disclosed in the following description.